Electrographic apparatus employing plural inkers of different colors for separating signal levels or channels according to color

ABSTRACT

An electrographic recorder is described which lays down a line of electrostatic charge on a charge retentive surface of a strip of electrographic recording paper. In one embodiment, the transverse position of the line charge image on the recording strip is representative of the amplitude of the signal being recorded. Plural inkers each dispensing a different color of charged pigment are arranged to ink charge images within separate strip-shaped zones of the recording strip. Thus, the inked electrostatic image will have a color dependent upon the amplitude range it happens to correspond to at any position taken longitudinally along the strip. The transverse position of the boundary between different colors is adjustable by sliding or pivoting the inkers, whereby the different colored amplitude ranges are made adjustable. In a second and third embodiment a multichannel recorder or printer is described wherein the signals corresponding to the different channels are each recorded in their own separate strip-shaped zone of the recording paper. Each separate recording zone has its own separate inker with pigment of a different color than that of its neighbors.

United States Patent [72] Inventor Renn Zapbiropoulos Los Altos, Calif.21 AppLNo. 871,706 [22] Filed Nov. 20, 1969 [45] Patented July 27, 1971[73] Assignee Varian Associates Palo Alto, Calif. Continuation ofapplication Ser. No. 612,540, Jan. 30, 1967, now abandoned.

[54] ELECTROGRAPHIC APPARATUS EMPLOYING PLURAL INKERS OF DIFFERENTCOLORS FOR SEPARATING SIGNAL LEVELS 0R CHANNELS ACCORDING TO COLOR 4Claims, 6 Drawing Figs.

[52] U.S. Cl 346/74, 101/1, 1l7/17.5, 118/637, 346/46 [51] Int. Cl Q01d15/06, G01d 9/10, 603g 13/10 [56] References Cited UNlT ED STATESPATENTS 2,044,586 6/1936 Marcellus 346/46 2,143,376 H1939 Hansell.....346/74X 3,270,349 8/1966 Murphy.... 346/46 3,277,493 10/1966 Fyler346/74 3,383,699 5/1968 Lapinskia. 3,434,878 3/1969 Reis PrimaryExaminer Bernard Konick Assistant Examiner-Gary M. Hoffman Attorney-LeonF. Herbert ABSTRACT: An electrographic recorder is described which laysdown a line of electrostatic charge on a charge retentive surface of astrip of electrographic recording paper. In one embodiment, thetransverse position of the line charge image on the recording strip isrepresentative of the amplitude of the signal being recorded. Pluralinkers each dispensing a different color of charged pigment are arrangedto ink charge images within separate strip-shaped zones of the recordingstrip. Thus, the inked electrostatic image will have a color dependentupon the amplitude range it happens to correspond to at any positiontaken longitudinally along the strip. The transverse position of theboundary between different colors is adjustable by sliding or pivotingthe inkers, whereby the different colored amplitude ranges are madeadjustable. In a second and third embodiment a multichannel recorder orprinter is described wherein the signals corresponding to the differentchannels are each recorded in their own separate strip-shaped zone ofthe recording paper. Each separate recording zone has its own separateinker with pigment of a different color than that of its neighbors.

PATENTED JULZHQT: 3.596 284 FIG. 3

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INVENTOR.

REhN ZAPHIROPOULOS BY (ah ATTORNEY ELECTROGRAPIIIC APPARATUS EMPLOYINGPLURAL INKERS OF DIFFERENT COLORS FOR SEPARATING SIGNAL LEVELS OF.CHANNELS ACCORDING TO COLOR This application is a continuation ofapplication Ser. N 0. 612,540 filed Jan. 30, 1967, now abandoned.

DESCRIPTION OF THE PRIOR ART Heretofore, electrographic recorders haveinked the charge image with one color of pigment regardless of itstransverse position on the recording paper. It is desired to have anelectrographic recorder that will change the color of the recorded tracewhen the signal falls below or exceeds a certain predeterminedamplitude. For example, if the recorder is recording the temperature ofsome device it is desirable to have the trace appear one color such asgreen when it is within a normal operating range of temperature and toappear another color such as red when the temperature is outside thenormal operating range.

Also, in multichannel recorders, where each recording channel isassigned a certain strip-shaped zone of the recording paper, it isdesirable to have the recorded signals for the different channelsrecorded with a different color trace such that the different channelsare more easily distinguished by an observer.

SUMMARY OF THE INVENTION The principal object of the present inventionis the provision of 'an improved electrographic recorder or printerapparatus.

One feature of the present invention is the provision of anelectrographic recorder or printer having two or more inkers dispensingcharged pigment particles of difi'erent colors onto separatestrip-shaped zones of the recording medium, whereby the charge imagesrecorded within the separate strip zones of the recording medium arerecorded in different colors. In one embodiment of the presentinvention, the color of a recorded signal can be made to change as thesignal amplitude changes from one range of amplitudes to another rangeof amplitudes. In another embodiment of the present invention, separatesignal channels can be allocated to separate strip-shaped zones of therecording medium for recording the signals of the separate. channels indifferent colors.

Another feature of the present invention is the same as that of thepreceding feature wherein the boundary between adjacent inking strips isadjustable by adjusting the positions of the different inkers relativeto the recording medium. In one embodiment of the present invention,this permits changing the range of amplitudes of the recorded signal orsignals corresponding to each of the separate colors. Inthe multichannelrecorder, it permits changing the width of the recording stripcorresponding to each of the separate channels.

Other features and advantages of the present invention will becomeapparent upon a perusal of the following specification taken inconnection with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. I is a schematic diagram of: an electrographic recorder employingfeatures of the present invention,

FIG. 2 is a schematic diagram of an adjustable inker of the presentinvention,

FIG. 3 is a schematic diagram of an alternative embodiment of anadjustable inker,

FIG. 4 is a schematic diagram of another alternative embodiment of anadjustable inker,

FIG. 5 is a schematic diagram of an alternative recorder embodimentemploying features of the present invention, and

FIG. 6 is a schematic diagram of a portion of a color image reproductiondevice employing features of the present invention.

. 2 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1,there is shown an electrographic recorder 1 incorporating features ofthe present invention. An electrical input signal to be recorded isapplied across a pair of input terminals 2 and 3. The input signal isfed to an error detector 4 wherein the input signal is compared with areference voltage derived from a potentiometer 5 to produce an error ordifference signal which is fed to an amplifier 6. The output of theamplifier 6 is fed to a reversible motor 7. The output shaft of themotor 7 drives the pickoff 8 of the potentiometer 5 via a mechanicallinkage 9. A recording stylus 11 is coupled to the mechanical linkage 9to move across a moving recording web 12 in variable accordance with theposition of the pickoff electrode 8.

A writing electrical potential as of 800 volts relative to ground isapplied to the writing stylus II. An isolating capacitor 13 separatesthe reference voltage from the writing voltage. The recording web 12 is,for example, an electrographic recording paper having a charge retentivedielectric film surface disposed adjacent the stylus 11 and a conductivepaper backing in contact with a conductive plate 14 operating at groundpotential.

The stylus 11 is, thus, caused to assume a transverse position (ordinateposition along the 0 axis) on the recording web 12 corresponding to thatreference voltage as picked otf the potentiometer 5 which just balancesout the input signal to be recorded. Therefore, the ordinate position ofthe stylus 11 corresponds to the amplitude of the input signal. The web12 is caused to move in the abscissa direction A in accordance with afunction against which the input signal is to be measured. For example,if the input signal is to be measured against time, the web 12 may bepulled past the stylus in the A direction at some predetermined rate.

The Writing stylus ll deposits a line-type change image I5 upon thecharge retentive surface of the web 12. A pair of inkers (pigmentapplicators) l6 and 17 are positioned over the web 12 to apply chargedpigment particles to the charge images for development (inking) thereof.The inkers 16 and 17 may be of any one of a number of different types.For example, they may comprise hollow channel members having an openside adjacent the web 12 with powdered pigment being carried as acolloidal suspension in an air stream. The particles are attracted outof the suspension by electrostatic attraction to the charge images. In apreferred embodiment, the pigment particles are applied by an open sidedchannel containing a flow of charged pigment particles colloidallysuspended in a liquid vehicle. The liquid is under less than atmosphericpressure such that the web is pressed up against the open side of theinking channel, sealing same. A suitable liquid inking channel isdescribed and claimed in copending U.S-. Pat. application No. 577,443filed Sept. 6, 1966, now U.S. Pat. No. 3,392,706 and assigned to thesame assignee as that of the present invention.

The inking channels 16 and 17 contain different colored pigmentparticles and are arranged across the web 12 to ink separate stripshaped zones 18 and 19 of the web 12. Thus, that portion of the chargeimage which falls within zone 18 is inked in a first color such as, forexample, red, whereas that portion of the charge image which fallswithin zone 19 is inked in a second color such as, for example, green.Since the zones 18 and 19 correspond to different amplitude ranges ofthe signal being recorded, the recording is in red when the amplitude ofthe signal being recorded exceeds some predetermined value correspondingto a line of demarcation 21 between the red and green zones 18 and 19,respectively. This is especially desirable for observation since itserves as a warning to the operator that the signal is above somepredetermined range of value and this is readily apparent with only themost cursory observation of the recording.

17 across the web 12 to a new location which offsets the line ofdemarcation 21 relative to its original position.

FIG. 2 shows an inking system wherein the inkers 16 and 17 are movableas a unit transversely of the web 12 to change the position of the lineof demarcation 21 between the red and green zones 18 and 19,respectively.

FIG. 3 shows an alternative arrangement for adjusting the line ofdemarcation 21. In this case, a partition member 22 which separates theinking chamber portions of the inking channels 16 and 17 is movabletransversely of the web 12 to move the line of demarcation 21.

Referring now to FIG. 4, there is shown another alternative arrangementfor adjusting the position of the line of demarcation 21 between theinking zones 18 and 19. In this case, the inking channels 16 and 17 arepivotable about points 23 and 24, respectively. The inkers 16 and 17 areeach pivoted to positions which will cause them to sweep adjacentstripshaped zones 18 and 19 of the web 12. The line of demarcation 21 isdefined by the boundary between the two zones 18 and 19.

Referring now to FIG. there is shown an alternative multichannelrecorder embodiment of the present invention. In this case, two separaterecorder channels 25 and 26, each similar to the recorder 1 of FIG. 1,are arranged within one recorder 27 to record their separate inputsignals upon separate strip-shaped zones 18 and 19 on a common recordingweb 12. Two inkers 16 and 17 are arranged to ink the charge imageswithin the separate strip zones 18 and 19, respectively. Differentcolored pigments are employed in the separate inkers 16 and 17 such thateach channel is recorded in a differentcolor, thereby facilitatingseparation of the recordings of the two separate channels.

Referring now to FIG. 6, there is shown another embodi ment of thepresent invention. More specifically, there is shown a portion of anelectrostatic printing and inking structure of a color imagereproduction apparatus employing electrographic techniques. The colorreproduction apparatus is v described and claimed in copending U.S. Pat.application No.

612,471 filed Jan. 30, I967 now US. Pat. No. 3,523,l58 and assigned tothe same assignee as the present invention. The color image reproducingdevice employs the separate channel inking feature of the presentinvention.

An array of fixed writing electrodes 31, only partially shown andgreatly enlarged in scale, are arranged across the electrographicrecording web 12 with the electrodes 31 having their ends disposedadjacent the charge retentive surface of the web 12. The electrodes 31are insulated from each other and arranged in groups 32 of three(triads). The first electrode R in each triad 32 is connected to a redcolor sensing and print circuit, not shown. The second electrode G ineach triad 32 is connected to a green color sensing and printingcircuit, not shown. The third electrode B in each triad 32 is connectedto a blue color sensing and printing circuit, not shown.

The sensing and printing circuits scan the color image to be reproducedline by line. Each circuit scans for its primary color content as theline is scanned. The respective color content signals are fed to therespective color printing electrodes R, G, or B. The electrodes 31 ofthe triads are selectively energized in accordance with the outputs ofthe three primary color circuits and cause line charge images to bedeposited upon the moving web 12. The electrodes are scanned at a varyrapid rate compared to the re at which the web 12 moves past theelectrodes 31. The line charge images are very narrow, i.e., or: theorder of 0.001 inches wide and very closely spaced to each other, i.e.,on the order of a 0.001 inches.

Three primary color inkers 33, 34 and 35 (red, green and blue) arespaced apart along the 'web 12 and each extends across the web 12. Theinkers 33, 34 and 35 each include an array of inking slots 36, 37 and 38cut through the sidewall of the inking channels 33-35 with each slotarray being positioned in registration with the respective colorprinting electrode 31 and charge image 15 to be inked. The slots 36-38have widths e ual to the widths of the charge ima es 15. Thus, the redinker 3 inks an array of narrow strip-s aped zones corresponding to allthe red" charge images and no other, while the green inker 34 inks anarray of narrow strip-shaped zones corresponding to only the green"charge images and the blue inker 35 inks an array of \narrowstrip-shaped zones corresponding to only the blue" charge images. Theresult is that the color image to be reproduced is printed on the web12. The resolution of the printed color image depends upon how narrowthe charge image lines 15 can be made and how narrow the separatestrip-shaped inking zones can be made. The inking channels 33,34 and 35are preferably adjustable in position across the web 12 in order tobring the slots 36-38 into precise registration with the electrodes 31and line charge images 15.

Since many changes could be made in the above construc tion and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in he accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

lclaim:

1. In an electrographic apparatus for providing a multicolored visibleimage on the charge retentive surface of a recording medium, thecombination comprising:

electrode means for forming an electric charge image upon the chargeretentive surface of the recording medium; means for moving therecording medium relative to the electrode means along a path of travel;

developing means including a first applicator portion and a secondapplicator portion spaced from the electrode means along the path oftravel for exposing the charge image to pigment particles of a first andsecond color respectively to provide a multicolored visible image, eachof the applicator portions being pivotally adjustable with respect tothe recording medium to define adjustable developing widths for thefirst and second colors.

2. The apparatus of claim 1, wherein the electrode means is an array ofmetallic electrodes extending across the recording medium.

3. The apparatus of claim 1, wherein the first applicator portion ispivotal about a first axis proximate one edge of the recording mediumand the second applicator portion is pivotal about a second axisproximate the other edge of the recording medium.

4. The apparatus of claim 3, wherein the applicator portions arepivotally secured together at a movable pivot point between the firstand second axis.

1. In an electrographic apparatus for providing a multicolored visibleimage on the charge retentive surface of a recording medium, thecombination comprising: electrode means for forming an electric chargeimage upon the charge retentive surface of the recording medium; meansfor moving the recording medium relative to the electrode means along apath of travel; developing means including a first applicator portionand a second applicator portion spaced from the electrode means alongthe path of travel for exposing the charge image to pigment particles ofa first and second color respectively to provide a multicolored visibleimage, each of the applicator portions being pivotally adjustable withrespect to the recording medium to define adjustable developing widthsfor the first and second colors.
 2. The apparatus of claim 1, whereinthe electrode means is an array of metallic electrodes extending acrossthe recording medium.
 3. The apparatus of Claim 1, wherein the firstapplicator portion is pivotal about a first axis proximate one edge ofthe recording medium and the second applicator portion is pivotal abouta second axis proximate the other edge of the recording medium.
 4. Theapparatus of claim 3, wherein the applicator portions are pivotallysecured together at a movable pivot point between the first and secondaxis.